Inside knurling tools



May 7, 1963 .1. c. GLAUM 3,088,344

INSIDE KNURLING TOOLS 2 Sheets-Sheet 1 Filed Nov. 16, 1959 May 7, 1963 J. c. GLAUM INSIDE KNURLING TOOLS 2 Sheets-Sheet 2 Filed Nov. 16, 1959 3,088,344 INSIDE KNURLING TOOLS John C. Gianni, 4621 N. Le Claire Ave., Chicago, lll. Filed Nov. 16, 1969, Ser. No. 853,200 1 Claim. (Cl Sil-5.1)

The present invention relates to knurling tools, and is particularly concerned with inside knurling tools adapted to be used in rehabilitating the bores of housings and work pieces which are intended to support bearings of the sleeve type or the outer races of 4anti-friction bearings.

One of .the objects of the invention is the provision of a knurling tool which is simple in construction, which has a minimum number of parts, which may be quickly adjusted and secured in centered position adjacent the bore to be knurled, and which is adapted to be manufactured at a low cost.

Another object of the invention is the provision of `an improved inside knurler vwhich accomplishes the positioning of the knurler -in centered position by 'the action of a pair of expanding knurlers which `assume a diametric position when they are expanded to maximum length inside a bore.

Another object of the -invention is the provision of an improved inside knurler which utilizes a minimum number of special parts, and which may therefore be manufactured more economically.

Another object of :the invention is the provision of an inside knurler which takes care of a wide range of diameters of the bores to be knurled so that a minimum number of separate tools is required -to handle all sizes of bores that are likely to be encountered.

Other objects and'advantages `of the invention will be apparent from the following `description and accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are two sheets,

`FIG. 1 is a top perspective view;

FIG. 2 is a fragmentary sectional Niew taken on the plane of the line 2-2 of FIG. l, looking in the direction of lthe arrows;

FIG. 3 i-s a fragmentary sectional view taken on the plane of the line 3-3 of FIG. 2, looking in the direction of the arrows;

FiG. 4 is a fragmentary bottom plan view;

FIG. 5 is a vfragmentary sectional view showing the application of the tool with its yguides and knurls to a bore at one side of the bore;

FIG. 6 is a side elevational view of an alternative form of knurl assembly.

Referring .to FIGS. 1 and 2, lthe present knurling tool preferably includes a supporting frame indicated in its entirety by the numeral 10, which is cruciform in shape and comprises a pair of steel bars -11 and 12 secured together at right angles to each other; and the bars are preferably of equal length and project radially equal distances from the central axis of the cruciform frame.

Each of the bars 11 and 12 is provided with a transverse centrally located rectangular groove, such as the groove 13 (FIG. 2) which is Wide enough to receive the other bar and deep enough -to receive half the thickness of the other bar, leaving a thin central body 14 on each bar so that the bars interlock and may be secured together with their upper and lower surfaces iiush with each other.

The bars are secured togetherby means of a hub 15, which comprises a -short cylindrical metal body of suflicient diameter to provideV room -for a pair of threaded bores 16, receiving threaded screw bolts 17 with countersunk heads :so that the heads are located in one bar; and the threaded shank'extends through both bars into a threaded bore in the hub 15, securing the bars together rigidly.

3,083,3-i Patented May 7, 1963 The hub 15 and the two bars are provided with an axial bore 18 located in .the axis of the frame and adapted to slidably receive a cylindrical shaft 19, which is provided with an elongated keyway 20 for receiving the key 21, which extends into a registering slot 22 in the hub.

The key 21 is elongated so as to per-mit longitudinal adjustment of the frame on the shaft; and the frame may be secured in any adjusted position by tightening a set screw 23 which is located in a threaded bore 24 in the hub.

The frame 10 has its cross bars each provided with au elongated through slot 25, 26, 27, 2S; and the slots are provided with rounded ends 29 tand 30 and extend to points adjacent the ends 31 of the bars. This permits a maximum adjustment ofthe guides 32-35 on the frame.

Each guide 32-35 comprises ia solid metal cylindrical body 36 having plane end surfaces 37, 38, and having an integral pin 39 projecting from one end of the cylinder and a threaded shank 4t? projecting axially from the other end of the cylindrical body.

The threaded shank of each guide passes through one of the slots 25-28 and has a guide nut 41 secured on the threaded shank 40. The guide nuts preferably have wide thin, radial flanges 42 for engaging the surfaces of the bars; and the 4guide nuts each preferably have .a pair of at sides 43 for engagement with the wrench in cl-amping the guides in place.

r[he pins 39 extend axially and are cylindrical and preferably have a limited length, such as, for example one-fourth to three-eighths of an inch; and the length of .the pins 39 determines the beginning position of -the knurl that is formed in the bore.

Bores are knurled because they have become enlarged and the bearings in them may be loose; and therefore the extreme outer end of the bore is not knurled by this tool, but is used as a bearing entering portion, which permits the bearing to `be started readily into its bore, the rest of which may be knurled to grip the bearing tightly.

Each guide is also provided on the side toward the nut with a metal pin 44 frictionally held in a bore and projecting from the back side of the body 36 to be lslidably engaged in one lof the slots 25-28, preventing rotation of the guide while the nut is being tightened.

The shaft 19 is provided at its outer end with a pair of opposed flat surfaces 45 for engagement with the handle-s 46, 47. These handles are identical and comprise square bars of steel provided at one end with aligned apertures 48, 49 for 'receiving the screw bolts 50, which pass through the apertures in one bar 46 and are threaded into the yapertures in the other bar 47.

The two handles 46, 47 are thus adapted to be clamped against the flat surfaces 45 on the end of the shaft and may be used for turning the shaft and actuating the knurling tool.

The shaft 19 is hollow yand has a cylindrical through bore 51 for receiving the inner shaft 52 by means of which the knurling tools are adjusted. At the outer end of the inner shaft 52 there is an adjustment knob 53, comprising a cylindrical metal body with a knurled edge 54 to be grasped by the fingers and having a smaller cylindrical hub 55 with a through bore 56 for receiving a driven pin 57, which .also passes through the shaft 52 and is iirictionally held in the hub and shaft to fasten these two members together.

At its other end the shaft 19 supports a knurl slider housing, comprising a rectangular block of metal having a bore 58 midway between its ends and adapted to receive the en'd of the shaft 19 to which it is secured by a metal pin 59 driven into a bore which intersects both the knurl slider housing 6) and the shaft 19, thus securing the housing on the shaft.

The inner shaft 52 is provided at its upper end (FIG.

2) with a bevel gear 61, which may be pinned or riveted Ourthe end of the shaft 52 and is adapted to be rotated by the knob 53.

The housing 60 is provided with a pair of aligned longitudinally extending slots 62, 63; and the housing 60 is provided with a transverse slot 64, providing space for` the :bevel gear 61, which is located closer to one wall 65 of the slot 64 than it is to the other wall 66. The reason for this is to provide space in the slot 64 for the second Abevel gear 67, which is carried by the screw shaft 68 by means of which the knurls are adjusted.

The housing 60 slidably supports a pair of knurl holders 69 and 70, each of which comprises an elongated rectangular block of steel adapted to slide in the slots 62, 63 and to be guided thereby for movement back and forth radially of the shaft 52. Each knurl holder 69 and 70 has a transverse vslot 71 or 72 extending into its end and leaving a pair of spaced ilanges 73, 74 at the end of each knurl holder for receiving the knurls 75, 76.

' The knurls 75, 76 each comprise substantially cylindrical rollers provided with the ribbed periphery 77, preferably having V shaped ridges and grooves extending parallel to the axis of each knurl roller. The knurls are hardened steel and the ridges thereon are adapted to form complementary vgrooves in the inside of the bore upon which the knurl is working; and each knurl is mounted upon a stub shaft 78 rotatably mounted in a bore 79 in each of the two flanges 73, 74.

' In one type of device there is a single knurling roll at each end; but in another modication, illustrated in FIG. 6, Vthere are three longitudinally extending flan-ges 80, 81, 82 separated by slots 83, 84 for receiving and rotatably supporting a pair of knurls 85, 86, which are preferably wide and suitably spaced with reference to the other Y knurl 77 so that the knurling peripheries of the rollers overlap each other yand produce a continuous knurled surface.

The double knurl holder is indicated by the numeral 87.

Each end of the guide member 60 is preferably formed with a partially cylindrical recess 88, 89 (FIG. 3), Permitting the knurls -to be retracted into the guide block, and permitting a wider range of operation.

The knurl actuating shaft 68 has the bevel gear 67 pinned or other wise Ifixedly secured in position to engage the bevel Vgear 61; and the shaft lis provided with a washer 9.0 (FIG. 2) for bearing against the adjacent surface of the guide block 60.

The shaft 68 has a right hand thread 91 at one end Yand a left hand thread 92 at the other end; and the sliding kknurl holders 69 and 70 have threaded bore 93 with a right hand thread and threaded bore 94 with a left hand thread extending into them for receiving the threaded shaft 68.

The knurl holders 69 and 70 are held in their guide slots by a Ycover plate 95, comprising a rectangular steel plateof the same size and shape as the guide block 60, koverlying the knurl holders 69 and 70 in their slots and secured in place by .a pair of screw bolts 96, 97, which pass through the cover plate and are threaded into the walls of the block 60.

Thus rectangular recesses are provided in the guide block 60 within which the knlirl holders slide, being held reach their maximum expansion in that bore.

and actuated -by the screw shaft 68, which in turn is held in place against rotation by friction and by the interengagement of the bevel gears 61 and 67.

The right and left hand threads 91, 92 on the shaft 68 constitute an irreversible screw mechanism for driving the knurls inward or outward into position in which the `knurls are positively held by the screw threads; but they may be projected or withdrawn' by rotating the knob 53.

The operation of the knurling tool is as follows: The vknurls are preferably withdrawn toward the frame 10 by meansof the shaft 19 sliding in the hub of the frame 10, where the frame may be secured by tightening the set screw 23. The parts are then in the position of FIG. 2.

At this expansion t-he diametrically opposite knurls will naturally seek a diameter in Ithe bore because a diameter represents the longest distance from the outer edge of one knurl to the outer edge of the other knurl. With the knurls adjusted to this position and tightly held in the bore, and the guide blocks 32-35 engaging the face of t-he casting, as shown in FIG. 5, the guide blocks are caused to slide in their slots 25-28 -until the pins 39 engage Vthe wall of the bore to be knurled.

The guide blocks are then tightened and set in this position by rotating the nuts 41. Each of the guides 32-35 is clamped in such posit-ion that its pin 39 engages the wall of the ybore to be knurled. l

The device is now centered in the ybore and is operated as follows: the shaft 19 is turned by means of the handles 46, 47, and from time toY time the knurls are expanded 'by rotating the knob 53, which rotates the innershaft 52 and drives the screw shaft 68 by means of the bevel gears 61, 67. A

The screw shaft drives the two knurl holders 69 and 70 outward in opposite directions and causes the knurls to bite into .the walls of the tbore being knurled, such as the 'bore 100 in FIG. 5, which shows one knurl 77 producing -a knurled surface l101 in the bore t100.

The rotation of the shaft 19 by means of the handles continues while the knurls are held in tight engagement with the wall of the bore 196; and as they knurl the wall, they are =fed outward until la maximum knurling is accomplished. The set screw 23 is then loosened Iand the knurls are withdrawn slightly inward in aradial direction; and the shaft 19 is moved farther into the bore to cause the knurls to engage a new surface, but the knurls are preferably so adjusted that they still overlap the iirst knurled surface 101.

The knurling may then continue until su'icient of the bore 100 is knurled to provide knurled surfaces for engaging the outside of the bearing. The knurling presses the metal in the -bore outward, forming V shaped ridges .at the same time the teeth on the knurl forrn V shaped grooves; Iand the bore in the casting is thus made effectively smaller and provided with a serrated surface which will hold the bearing against axial movement or -against rotation, gripping the bearing more effectively than it may have been gripped originally by the Smooth sunface of the Ibore.

It -will thus be observed that I have provided a novel knurling tool which is simple in its construction, which has a minimum number of parts, which requires a minimum number of knurls and knurl holders, and is still adapted to be centered most easily. t

I have found that it is not necessary to provide triple contact `of knurls in the bore to center the tool and that the tool is eectively centered by having two knurl holders located on the same diameter. Y

The present tool may be manufactured more `economically than the devices of the prior art and may be sold ata lower price, which places it within the reach of a larger number of users. Y

While I have illustrated a preferred embodiment of my Y invention, many .modifications may be made Without departing from the spirit of the invention, and E[ do'not wish to be limited to the precise details of construction set lforth, but desireto avail myself of all changes within the scope of the appended claim.

l claim:

An inside knurling tool -for knurling concentrically the inner surfaces of a bore in a body supporting a bearing of the bushing type, comprising -a frame adapted to be located and held concentric to the bore in said body, said frame having four radially extending arms, and each ar-m having a radially extending slot for supporting a guide member, each guide member having -a circular head lolcated on the back side of said rframe, and a cylindrical guide vpin projecting axially from said circular head and surrounded by an annular shoulder for engaging the body outside o-f its bore, e-ach guide member having an axially extending threaded shank projecting forwardly from said head and slidably mounted in one of said slots in the arms of said frame, a threaded member on each threaded shank and engaging the frame -arm in which the threaded shank is located, said frame having an axially extending bore and a shaft in said bore, said shaft having an `actuating handle on its outer end and having a through bore concentric With said shaft, and said shaft supporting a di-ametrically located knurl bar guide on its inner end, said bar guide having a pair of rectangular section knurl bars sliding radially in said -bar guide, each knurl bar having a rotatable knurl at its outer end and an axial threaded bore with right hand and left hand threads in the respective knurl bars, and a complementarily threaded knurl actuating shaft engaging said ri-ght hand and left hand threads in the knurl bars and having a bevel gear on said knurl actuating shaft and engaging a bevel `gear on the shaft located in said axial bore, said latter shaft having a knurl adjusting head on its outer end, said knurls being iirst retracted to be received in the bore to be knurled and then expanded into centering engagement with said bore with the guides retracted until the Aguide pins enter said bore and the annular `sur-face surrounding each guide pin engages the said lbody outside the bore to be knurled, said guide members then having their guide pins moved out into engagement with the inner wall of the bore to be knurled, and each Iguide member being secured in this position by its threaded Amember clamping said 'frame in fixed position in the bore to be knurled, the :frame guiding the axial shaft while it is rotated by Said handle 4and while the `knurl bars are moved out by turning the -knurl adjusting head to cause the knurls to knurl the inner surface eoncentrically.

References Cited in the le of this patent UNITED STATES PATENTS Re. 24,714 Bennett et al Oct. 6, 1959 656,952 Dornheim Aug. Q8, 1900 1,382,932 Ramsdell June 28, 1921 1,904,109 Wendorf April 6, 1932 1,956,338 Eggimann July 10, 1934 2,618,182 Teetor Nov. 18, 1952 FOREIGN PATENTS 24,251 Denmark Mar. 10, 1919 117,624 Sweden Nov. 12, 1946 870,627 Germany Mar. 16, 1953 

